Buggy code:
public class JJTree extends Task { private static final String OUTPUT_FILE = "OUTPUT_FILE" ; private static final String BUILD_NODE_FILES = "BUILD_NODE_FILES" ; private static final String MULTI = "MULTI" ; private static final String NODE_DEFAULT_VOID = "NODE_DEFAULT_VOID" ; private static final String NODE_FACTORY = "NODE_FACTORY" ; private static final String NODE_SCOPE_HOOK = "NODE_SCOPE_HOOK" ; private static final String NODE_USES_PARSER = "NODE_USES_PARSER" ; private static final String STATIC = "STATIC" ; private static final String VISITOR = "VISITOR" ; private static final String NODE_PACKAGE = "NODE_PACKAGE" ; private static final String VISITOR_EXCEPTION = "VISITOR_EXCEPTION" ; private static final String NODE_PREFIX = "NODE_PREFIX" ; private final Hashtable optionalAttrs = new Hashtable ( ) ; private String outputFile = null ; private static final String DEFAULT_SUFFIX = ".jj" ; private File outputDirectory = null ; private File target = null ; private File javaccHome = null ; private CommandlineJava cmdl = new CommandlineJava ( ) ; public void setBuildnodefiles ( boolean buildNodeFiles ) { } public void setMulti ( boolean multi ) { } public void setNodedefaultvoid ( boolean nodeDefaultVoid ) { } public void setNodefactory ( boolean nodeFactory ) { } public void setNodescopehook ( boolean nodeScopeHook ) { } public void setNodeusesparser ( boolean nodeUsesParser ) { } public void setStatic ( boolean staticParser ) { } public void setVisitor ( boolean visitor ) { } public void setNodepackage ( String nodePackage ) { } public void setVisitorException ( String visitorException ) { } public void setNodeprefix ( String nodePrefix ) { } public void setOutputdirectory ( File outputDirectory ) { } public void setOutputfile ( String outputFile ) { } public void setTarget ( File target ) { } public void setJavacchome ( File javaccHome ) { } public JJTree ( ) { } public void execute ( ) throws BuildException { Enumeration iter = optionalAttrs . keys ( ) ; while ( iter . hasMoreElements ( ) ) { String name = ( ( String ) ( iter . nextElement ( ) ) ) ; Object value = optionalAttrs . get ( name ) ; cmdl . createArgument ( ) . setValue ( ( ( ( "-" + name ) + ":" ) + ( value . toString ( ) ) ) ) ; } if ( ( ( target ) == null ) || ( ! ( target . isFile ( ) ) ) ) { throw new BuildException ( ( "Invalid<seq2seq4repair_space>target:<seq2seq4repair_space>" + ( target ) ) ) ; } if ( ( outputFile ) != null ) { cmdl . createArgument ( ) . setValue ( ( ( ( "-" + ( JJTree . OUTPUT_FILE ) ) + ":" ) + ( outputFile . replace ( '\\' , '//' ) ) ) ) ; } File javaFile = null ; if ( ( outputDirectory ) == null ) { javaFile = new File ( createOutputFileName ( target , outputFile , null ) ) ; } else { if ( ! ( outputDirectory . isDirectory ( ) ) ) { throw new BuildException ( ( ( "'outputdirectory'<seq2seq4repair_space>" + ( outputDirectory ) ) + "<seq2seq4repair_space>is<seq2seq4repair_space>not<seq2seq4repair_space>a<seq2seq4repair_space>directory." ) ) ; } cmdl . createArgument ( ) . setValue ( ( "-OUTPUT_DIRECTORY:" + ( outputDirectory . getAbsolutePath ( ) . replace ( '\\' , '//' ) ) ) ) ; javaFile = new File ( createOutputFileName ( target , outputFile , outputDirectory . getPath ( ) ) ) ; } if ( ( javaFile . exists ( ) ) && ( ( target . lastModified ( ) ) < ( javaFile . lastModified ( ) ) ) ) { log ( ( ( "Target<seq2seq4repair_space>is<seq2seq4repair_space>already<seq2seq4repair_space>built<seq2seq4repair_space>-<seq2seq4repair_space>skipping<seq2seq4repair_space>(" + ( target ) ) + ")" ) , MSG_VERBOSE ) ; return ; } cmdl . createArgument ( ) . setValue ( target . getAbsolutePath ( ) ) ; cmdl . setClassname ( JavaCC . getMainClass ( javaccHome , TASKDEF_TYPE_JJTREE ) ) ; final Path classpath = cmdl . createClasspath ( getProject ( ) ) ; final File javaccJar = JavaCC . getArchiveFile ( javaccHome ) ; classpath . createPathElement ( ) . setPath ( javaccJar . getAbsolutePath ( ) ) ; classpath . addJavaRuntime ( ) ; final Commandline . Argument arg = cmdl . createVmArgument ( ) ; arg . setValue ( "-mx140M" ) ; arg . setValue ( ( "-Dinstall.root=" + ( javaccHome . getAbsolutePath ( ) ) ) ) ; final Execute process = new Execute ( new org . apache . tools . ant . taskdefs . LogStreamHandler ( this , Project . MSG_INFO , Project . MSG_INFO ) , null ) ; log ( cmdl . describeCommand ( ) , MSG_VERBOSE ) ; process . setCommandline ( cmdl . getCommandline ( ) ) ; try { <START_BUG> if ( Execute . isFailure ( process . execute ( ) ) ) { <END_BUG> throw new BuildException ( "JJTree<seq2seq4repair_space>failed." ) ; } } catch ( IOException e ) { throw new BuildException ( "Failed<seq2seq4repair_space>to<seq2seq4repair_space>launch<seq2seq4repair_space>JJTree" , e ) ; } } private String createOutputFileName ( File target , String optionalOutputFile , String outputDirectory ) { } private boolean isAbsolute ( String fileName ) { } }

Fix:
if ( ( process . execute ( ) ) != 0 ) {